A131094 Triangle where n-th row contains the smallest n positive integers (listed in order) with exactly n nonleading 0's in their binary representations.

2, 4, 9, 8, 17, 18, 16, 33, 34, 36, 32, 65, 66, 68, 72, 64, 129, 130, 132, 136, 144, 128, 257, 258, 260, 264, 272, 288, 256, 513, 514, 516, 520, 528, 544, 576, 512, 1025, 1026, 1028, 1032, 1040, 1056, 1088, 1152, 1024, 2049, 2050, 2052, 2056, 2064, 2080, 2112

Offset

1,1

Links

Reinhard Zumkeller, Rows n = 1..125 of triangle, flattened

Example

Binary representations of the terms in the first few rows:
10
100, 1001
1000, 10001, 10010
10000, 100001, 100010, 100100

Maple

A080791 := proc(n) local bdigs ; bdigs := convert(n, base, 2) ; nops(bdigs)-add(i, i=bdigs) ; end: A131094 := proc(n) local a, i; a := [] ; i := 2^n ; while nops(a) < n do while A080791(i) <> n do i := i+1 ; od: a := [op(a), i] ; i := i+1 ; od: RETURN(a) ; end: seq(op(A131094(n)), n=1..10) ; # R. J. Mathar, Oct 17 2007

Prog

(Haskell)
import Data.List (sort, nub)
a131094 n k = a131094_tabl !! (n-1) !! (k-1)
a131094_row n = a131094_tabl !! (n-1)
a131094_tabl = [2] : f 2 [2] where
   f v ws = ys : f (v + 1) ys where
            ys = take v $ nub $ sort $ concatMap h ws
   h z = [2 * z, 4 * z + 1, 4 * z' + b] where (z', b) = divMod z 2
-- Reinhard Zumkeller, Feb 11 2015

Crossrefs

Cf. A081118, A131095.

Sequence in context: A179219 A367726 A033149 * A129598 A256017 A125752

Adjacent sequences: A131091 A131092 A131093 * A131095 A131096 A131097

Keyword

nonn,tabl

Author

Leroy Quet, Jun 14 2007

Extensions

More terms from R. J. Mathar, Oct 17 2007

Status

approved